The present invention relates to a treatment of a copper alloy surface and more particularly to the treatment of a beryllium copper surface prior to electroplating.
Various systems for treating beryllium copper prior to electroplating exist in the prior art. These systems basically involve attacking the copper and the beryllium on the surface thus leaving a new surface essentially similar to the initial beryllium copper surface but clean (i.e. free from contaminants, impurities, and some beryllium compounds). However, due to the tenacity of beryllium compounds and the instantaneous formation of new ones these systems provide less than satisfactory results in many cases resulting in poor adhesion of plate in certain areas on the plated surface. Often some beryllium compounds are left on the surface after the preplating treatment and these areas where the beryllium compound exists result in places which cannot be properly activated for plating. This entire plating problem of the beryllium is increased when a continuous automated strip treatment and plating process is desired. Typically prior art processes for the treatment of the beryllium copper prior to electroplating require too long a time in solution to reasonably provide for a continuous strip operation.
There has thus been an unfulfilled need in the art for a reliable practical means for treating beryllium copper prior to plating, particularly means which provides for a continuous automatic strip process.
Accordingly an object of the present invention is to provide an improved process for treating a beryllium copper surface.
Another object of the present invention is to provide a process for treating beryllium copper material prior to electroplating which allows for uniform consistent void-free plating.
Yet another object of the present invention is to provide a process for treating a continuous strip of beryllium copper prior to electroplating which is simple and economical and creates a uniform void-free plated surface. Other objects and features will be in part apparent and in part pointed out hereinafter.
Briefly, the present invention involves a process for the treatment of beryllium copper prior to electroplating comprising the steps of degreasing the material, removing the beryllium from the surface thereby leaving a copper rich area and activating the copper rich surface area for plating. A vapor degreaser is preferably used to remove greases and oils from the material. Then an alkaline solution having a high solubility for beryllium is used along with anodic electrolysis in order to form beryllium compounds both directly on the surface and in material layers directly below the surface. Next the beryllium compounds are dissolved in a sulfuric acid bath thus leaving a copper rich portion on and near the surface. Finally the copper enriched portion is put through a copper activating bath to reduce any copper compounds formed in order to prepare the material for plating.